The clinical trial literature on surfactant clearly demonstrates that surfactant therapy results in improved early respiratory status and improved mortality rates for premature newborns infants suffering from respiratory ailments due to surfactant insufficiency. However, the clinical trial experience regarding efficacy does not ensure that the same benefits will be conferred on patients outside the clinical trial environment during routine medical care. The work proposed under this grant application is designed to identify what happened to specific groups of newborns after surfactant was introduced to the market. Were the same benefits with regard to morbidity, mortality, and resource use in evidence post treatment IND? These authors have already demonstrated in an epidemiological study published in the New England Journal of Medicine (May 1994) that morbidity, mortality, and resource use among very low birth weight inborn infants declined once surfactant became available. This study will broaden the focus to include infants excluded from our original study. Our hypotheses for the proposed work center on our belief that infants who are in the 1500 to 2500 gram weight group also experienced reduced mortality, morbidity, and resource use post-surfactant, as did those who are mature with severe respiratory disease, and those who are outborn i.e. those who are transferred to a perinatal center. We have specified three similar hypotheses for each of these groups of patients. Finally, because of the significant focus on health care reform an& quality assurance in clinical care we have included a hypothesis focusing on the impact of payer on mortality, morbidity, and resource use. Our original study identified that payer was not a factor differentiating the newborns with regard to any of our measures of outcome or resource use. We have hypothesized that his will remain the case. However, we suspect that there may be some indications in our analysis among patients who are outborn that HMO or managed care is influencing not only where births are Occurring but how well fragile newborns do in the clinical environment. All the analyses proposed are planned to be accomplished within a two year time frame using analytic datafiles from the National Perinatal Information Center's Perinatal Center Database. A pre-and post-surfactant period will be created using eleven perinatal centers who provided data on all newborns from 1985 and 1992. Infants will be divided into two groups according to whether they were born before or after surfactant was introduced into clinical practice. Regression models controlling for race, sex, and birthweight will be used to assess morbidity, mortality, and resource use.